The present invention relates to bearing assemblies, and more particularly to a snap fit bearing assembly including a snap fit device for mounting a securable and removable bearing of a rotatable member to a wall of a machine, such as a wall of an electrostatographic reproduction machine.
Electrophotographic or electrostatographic marking is a well-known, commonly used method of copying or printing documents. Electrophotographic marking is performed by exposing a charged photoreceptor with a light image representation of a desired document. The photoreceptor is discharged in response to that light image, creating an electrostatic latent image of the desired document on the photoreceptor""s surface. Toner particles are then deposited onto that latent image, forming a toner image, which is then transferred onto a substrate, such as a sheet of paper. The transferred toner image is then fused to the substrate, usually using heat and/or pressure, thereby creating a permanent record of the original representation. The surface of the photoreceptor is then cleaned of residual developing material and recharged in preparation for the production of other images. Other marking technologies, for example, electrostatographic marking and ionography are also well-known.
An electrophotographic marking machine generally includes bearings for supporting and connecting parts, for example, a shaft. While such bearings are generally successful, fastening of the bearing to a member may be time consuming and costly. Bearings may add to the cost of the machine. Further, the bearing may wear or fail and cause inefficient operation of the machine. In addition, manufacturing time is required to install the bearings and to connect the components to the bearings during assembly of the machine.
Also, to conserve natural resources and provide for a machine with improved features and more reliable newer technology, machinery is often remanufactured and disassembled. Furthermore, the removal of the bearings represents a cost associated with remanufacturing of the machines. The time required to remove bearings may be a significant remanufacturing cost factor. Components have typically been joined together with the use of bearings in the form of welding, rivets or screws. Rivets require the use of special machinery to assemble, may become loose and rattle during use and are difficult and expensive to remove for remanufacturing. Screws have disadvantages in that they require a substantial amount of assembly time, may become loose during use, and may become very time consuming to remove. Therefore, a bearing that may be easily manufactured and that is removeably securable to a surface for use with other parts would be beneficial.
Moreover, it has been increasingly important to develop lighter materials for the framework of the machines. Accordingly, many modem machines utilize a fabricated sheet metal or plastic frame resulting in relatively thin walled support structures. Throughout a typical printing machine, there are many shafts utilized to support idler rollers, drive rollers. It is therefore desirable to provide a bearing which can be utilized in a wall while still providing generally high durability.
Reference is made for example to U.S. Pat. No. 6,024,497 (Liebman) which relates to a bushing mountable in a housing for supporting a rotating member and for providing a bias force to the rotating member. The bushing includes a body defining an aperture therein and a mounting member for mounting the bushing to the housing. The bushing also includes a biasing member operably associated with said body and said mounting member.
U.S. Pat. No. 5,511,885 (Coleman) relates to a plain flanged bearing or bushing for supporting a rotating shaft in a thin walled frame of an electrophotographic printing machine. The composite bearing has a flanged end and is adapted to be inserted in an opening in a thin walled support member until the flange abuts the surface of the wall. A protruding tab formed by displacing a small portion of the flange extends in an axial direction along the bearing and cooperates with a corresponding opening in the wall to prevent rotation of the bearing. A friction push nut or snap ring is attached to the bearing on the side of the wall opposite the flange. The protruding tab prevents the bearing from rotating about an axis which can cause the bearing to be worn on the exterior surface by rotational contact with the thin wall. A shaft to support idler rolls or other rotating elements is inserted in an inner bore of the bearing and is rotatably supported thereby.
In accordance with one aspect of the present invention, there is provided, a snap fit bearing assembly for supporting a rotatable shaft in a wall of a machine. The snap fit bearing assembly includes a support wall portion, of the machine, having a first surface, a wall thickness and a second and opposite surface; a central opening through the support wall portion; a bearing receiving recess formed from the first surface partially into the wall; plural receiving openings formed through the wall thickness and spaced from the central opening; a bearing device having an inner bore and an external surface for inserting into the bearing receiving recess; and an adjustable force applying spring clip for applying a desired normal force to the bearing device. The adjustable force applying spring clip includes a chest portion for contacting the bearing device; resilient shoulder portions bent towards a back surface of the chest portion and connected one to each of first and second edges of the chest portion; and first and second hand portions connected one to each of the first and second resilient shoulder portions, and bent forwardly from the first and second resilient shoulder portions for snapping into a first and a second receiving openings of the plural receiving openings through the wall thickness of the support wall portion.